The present invention relates to method and apparatus for placing layups of sheet material on the support surface of a cutting or other work table in preparation for a cutting or other work operation. More particularly, the present invention relates to method and apparatus for moving pre-formed layups of limp sheet material onto the work table by means of a sled and then removing the sled once the layup is in its proper position for working.
Automation has greatly improved the speed, accuracy and economics of cloth cutting and other work processes to the the point where material-handling procedures before and after the work process become materially significant to overall output. In manufacturing garments, upholstery and many other products made from limp sheet material, a multi-ply layup of the limp sheet material is generally cut by means of a machine having a tool head including a reciprocating knife blade which penetrates through the layup and translates along cutting paths under computer control. One such automatically controlled cutting machine is disclosed in U.S. Pat. No. 3,495,492 having the same assignee as the present invention. In the patented machine, the tool head is translated by carriages in two coordinate directions over the penetrable support surface of a cutting table on which the layup is firmly held during the cutting operation. The penetrable surface may be constructed from blocks of foamed plastic or bristled mats so that the reciprocating knife blade can penetrate entirely through the layup of limp sheet material without damage. For a more detailed description of the cutting machine, and its operation, reference may be had to the mentioned patent.
It will be recognized that the time required to form or generate a layup on the support surface of the cutting table steals from the useful operating time of the cutting machine. The sheet material is formed in the layup on the table by spreading one ply on top of another, and during the spreading operation, the cutting tool head and supporting carriages cannot operate and are parked at a rest position on the cutting table.
More economical use of the tool head, the carriages and the numerical controllers which govern or regulate the operation of the tool head on the cutting table can be achieved by providing several different cutting tables for each tool head and controller; and by transferring the tool head between the several different tables. Thus, the cutting blade can be operating upon a layup on one of the cutting tables while layups are being formed on or cut pattern pieces are being removed from the other tables. Apparatus for transferring the cutting machine between the plurality of such tables is disclosed in U.S. Pat. No. 3,776,074 having the same assignee as the present invention.
Another solution which increases the utilization of the cutting machine comprises pre-forming of the layups at a position remote from the cutting table and moving the layup onto the cutting table in its pre-formed condition. The present invention is directed to this solution.
It is, accordingly, a general object of the present invention to provide a method and apparatus for placing a pre-formed layup of limp sheet material on the support surface of a cutting table in preparation for a cutting operation.